Art of cracking hydrocarbon oils



lully 23, 11929. E. c. HERTHEL ART OF CRACKING HYDROCARBON OILS Filed Jan. l2, 1928 Patented July 23, 1929.

UNITED STATES 1,721,780 PATENT OFFICE.

EUGENE C. HERTHEL, `OI? CHICAGO, ILLINOIS, ASSIGNOR T SINCLAIR REFINING COM- IPANY, OF NEW YORK, N. Y., A CORPORATION 0F MAINE.

ART or CRACKING HYDROCARBON oILs.

Application filed January 12, 1928.

by distillation under superatmospheric pressure: more particularly the invention relates to improvementsv in apparatus for carrying out pressure distillationcracking operations.

The apparatus of the present invention is of special value and application in connection with an improved process of cracking hydrocarbon oils described and claimed in an application copending herewith tiled January 12.41925. Serial No. 246,262.

One form of apparatus embodying the invention is illustrated in the accompanying drawings. grammatically and conventionalljv represent a pressure still system, in elevation andv partly in section with parts broken away, embodying the invention.

Referring to the drawings, the pressure still s vstem illustrated comprises a batter)v of heating tubes 2 arranged in the heating flue of a furnace 3, a vaporizing drum 4, circulating connections, 5, (5 and T including a pump or other suitable forcing means S, these connections and the forcing means being arranged for circulating oil from the vaporizing drum upwardlrv through the heating tubes and back to the vaporizing drum, a valve 9 for closing the connection between the vaporizing drum t and the intake side ofthe forcing means S, a reliux tower 10 with vapor connections 11 and reflux return connections 12 t0 the still proper, a connectlon 13 for introducing raw oil into the reflux tower 10, a'condenser 14, a receiver 15, and a connection 16 for discharging unvaporized oil from the vaporizing drum 4. Connection 17 is provided for discharging the distillate product and connection 18 for discharging uncondensed vapors and gases from receiver 15. Pressure in the system may be maintained and regulated bv means of valve 19 in the vapor line 2O between the refiux tower 10 and the condenser 14, or by lneans of suitable valves arranged bevond the condenser or receiver. Connection 21 is provided for initially charging the still at the beginning of a run and for pumping out the still at the end of arun. Connection Q2 is provided for supplying cool oil, for example, cool raw oil to be supplied to the still s vstem` to or through the bearings of the forcing means 8. Con- The accompanying drawings dia- Serial No. 246,263.

nections 23, including suitable forcing means, are provided for rccirculating over the heating tubes a portion ofthe heating gases which have passed thereover, as described in Letters Patent No. 1,574.516 and No. 1,5Tl,5l7 issued to the Sinclair Refining Company February 23, 19:26, on applications of John E. Bell.

T he connection 5 for circulating oil from the vaporizing drum 4 to the. heating tubes opens upwarcl)v into the vaporizing drum below the normal liquid level therein. The valve proper is arranged at the upper end of this connection. The form of valve illustrated, which is particularly advantageous, comprises a conical closure member arranged to seat in the circular opening between the vapor-vaporizing drum -l and the circulating connection For raising and lowering the conical member 9, an operating extensionQsl is attached thereto and carried through the wall of the vaporizing drum through a stuit'- ing box 25 arranged above the normal liquid level, the operating extension passing upwardly through the vaporizing drum and through the1 vapor space therein. The operating extension Q1 is, with advantage, rigidly fixed to the closure member 9 so that all parts of the valve mechanism xexposed to high temperatures` and hot oil in the still are of extreme simplicity. After passing through the stuffing box 25, the operating extension 24 ma",v be carried by a threaded yoke or any other suitable means for raising and lowering the closure member of the valve from and to the seat. lvith this arrangement, none of the operating parts of the valve mechanism moving with respect to each other are exposed to high temperatures or hot oil in the still, excepting the closure member and seatV and the inside of the stuffing box through which the operating extension passes. This exposed portion of the stutling box, moreover,

is exposed only to the vapors within the still which are of rclativel)v low heatcapacity as compared to the liquid oil therein and which are free from suspended solids or semi-solids.

The reflux return connections 1:2 open into circulating connection 5 between valve 9 and the intake side ofthe forcing means 8. Yith this arrangement the change from circulation of admixed reflux condensate and unvaporized oil from thc vaporizing drum through the heating tubes to circulation of refiux condensate therethrough withoutadmixture of unvaporized oil from vaporizing drum or 'vice versa can be made simply by closing or opening respectively valve 9. In the apparatus illustrated, raw oil introduced into the reflux tower 10 through connection 13 leaves the reflux tower through connection 12 and .enters the circulating connection 5 in admixture with reflux condensate' from the reflux tower.

In one way of operating thel apparatus of the invention, after an initial charge of' oil is brought to cracking conditions of temperat-ure and pressure, the still charge is during an initial period of operation circulated and recirculated through the heating tubes from and to the vaporizing drum and in a subsequent period of operation the recirculation of unvaporized oil from the. vaporizing drum is stopped and only reflux condensate or raw oil or adlnixed raw oil and reflux condensate is circulated through the heating tubes to the \-'aporizing drum, the change in operation between this initial and this subsequentperiod being effected by closing the valve 9. The apparatus of the invention, however. is gcnerally useful in operations in which this change or the reverse change, or both, is to be made.

The invention is specifically described therein With reference to the particular form of apparatus illustrated in the accompanying drawings, but it is intended and will be uni derstood that this detailed illustration is for the purpose of exemplification rather than limitation. y

I claim:

A pressure still system comprising a vaporizing drum and a battery of heating tubes, a connection opening upwardly into the vaporizing drum below the normal liquid level therein for circulating oilfroin the Vaporizing drum to the heating tubes, Ya forcing means in said connection, a connection for circulating oil from the heating tubes to the Vaporizing drum, a reflux tower and vapor connection between the same and lthe vapor space of the vaporizing drum, a valve arranged at the upper end of said first mentioned connection and an operating extension therefor extending upwardly through the vaporizing drum and through the vapor space Within the same and passing through the Wall of the vaporizing drum above the normal liquid level therein, and a reflux return connection from the reflux tower opening into said firstl mentioned connection between said valve and said forcing means.

In testimony whereof, I have subscribedmy name.

EUGEN c. HERTHEL. 

